基于物元模型的沥青路面使用性能评价分析

依据重庆地区数条高速公路的检测数据,采用基于物元法建立的综合评价模型对路面使用性能进行综合评价,并将评价结果和使用现行的路面使用性能综合评价指标PQI所得结果进行比较分析。     

基于等维递补灰色理论的沥青路面预防性养护研究

本文针对我国预防性养护现状,分析了路面使用性能评价指标,提出了等维递补灰色理论预测路面评价指标体系的方法,并对京沪高速PCI进行预测,结果表明预测方法正确、可行。     

旧水泥混凝土路面路用性能评价方法

基于结构承载力、平整度、破损状况评价等三方面对旧水泥路面路用性能进行研究,提出了路表弯沉值,三米直尺连续测得路面不平整的统计标准差,路况指数PCI这三个评价指标,并建立了路面使用性能评价模型,进一步提出基于回归模型的评价方法不适合于高等级公路路面使用性能的综合评价的结论.     

基于PNN模型和RF模型的沥青路面使用性能预测研究

如何准确地预测评断沥青路面使用性能,对于道路养护起着至关重要的作用。为了提出更为准确的路面使用性能评价方法,在规范所提出的评价指标的基础上,以临沂市的沥青路面使用评价相关数据为研究对象,分别基于概率神经网络（PNN）模型和随机森林（RF）模型,构建沥青路面使用性能预测模型,以此为沥青路面使用性能状态预测、科学制定沥青路面养护决策提供参考。     

基于可拓学理论的道路使用性能评价方法评析

文章简要论述了常见的道路使用性能评价方法,提出了利用可拓学理论构建道路使用性能等级评价模型,并采用实例加以验证。与规范的对比结果表明,基于可拓学理论的路况评价模型达到了评价道路使用性能的效果,该方法对道路的养护决策具有积极的指导意义。     

基于层次分析-理想点法的路面使用性能评价

文章针对现阶段路面使用性能评价方法存在的不足,运用层次分析法与理想点法原理,建立了基于层次分析-理想点法的路面使用性能评价模型,并将该模型运用到现有高速公路路面使用性能评价中,并与规范和灰色理论方法的判定结果进行对比分析,验证了该模型应用于路面使用性能评价的可靠性与合理性。     

广西地区高速公路沥青路面养护措施评价研究

针对目前广西地区高速公路沥青路面养护状况,文章依托实体工程,通过路面养护数据和使用性能检测数据的收集、整理和分析,对微表处、不同厚度的铣刨重铺等常用沥青路面养护措施的使用效果进行评价,其对广西地区高速公路沥青路面养护方案的制定具有借鉴意义。     

G306国道(葫芦岛段)沥青路面使用性能评价及分析

根据G306国道施工,简要介绍了我国规范所使用的评价模型,并做了适当的添加.根据对G306国道各单项使用性能指标的统计,分析了其路面使用性能及特点,并作出结论.     

公路路面沥青综合表面处治层质量评价方法研究

文章基于公路路面沥青综合表面处治试验路段性能指标检测,确定使用构造深度和饱和度评价公路路面沥青综合表面处治的使用性能,并利用主成分分析法对公路路面沥青综合表面处治层进行了质量评价。结果表明,该评价方法是合理、可行的。     

沥青路面平整度影响因素控制

路面平整度是评价高等级公路路面使用性能的一个重要指标.针对影响沥青路面平整度的原因进行了分析,并对施工控制方面提出了相应的措施,来提高路面工程质量.     

Incorporating time and income constraints in dynamic agent-based models of activity generation and time use: Approach and illustration

Existing theories and models in economics and transportation treat households’ decisions regarding allocation of time and income to activities as a resource-allocation optimization problem. This stands in contrast with the dynamic nature of day-by-day activity-travel choices. Therefore, in the present paper we propose a different approach to model activity generation and allocation decisions of individuals and households that acknowledges the dynamic nature of the behavior. A dynamic representation of time and money allocation decisions is necessary to properly understand the impact of new technologies on day to day variations in travel and activity patterns and on performance of transportation systems. We propose an agent-based model where agents, rather than acting on the basis of a resource allocation solution for a given time period, make resource allocation decisions on a day-by-day basis taking into account day-varying conditions and at the same time respecting available budgets over a longer time horizon. Agents that share a household interact and allocate household tasks and budgets among each other. We introduce the agent-based model and formally discuss the properties of the model. The approach is illustrated on the basis of simulation of behavior in time and space.     

一种新型管道机械接头密封分析

随着海洋石油事业的发展,尤其是在役多年的石油平台工艺管道长时间受腐蚀介质和海洋环境的影响容易发生泄漏,传统的管道焊接技术由于需要动火作业,在已投产的石油平台管道维修方面受油气易燃易爆等各种因素的制约,不适应海洋平台管道维修快速、环保、经济等新要求。文中利用ANSYS有限元软件对传统机械接头的结构进行优化分析,开发出一种新型管道机械连接接头。此种接头具有耐高压、耐腐蚀、节能、安全、安装快捷等显著优点,特别适用于海洋石油平台工艺管道的快速维修。着重分析了新型管道机械接头的基本结构、连接机理及影响其密封性能的主要因素,分析结果显示此种连接可靠。     

Derivation of train arrival timings through correlations from individual passenger farecard data

Transportation - In this paper, we propose a method for estimating the timings at which trains arrive and depart from stations using passenger farecard data and knowledge of the network topology....     

卡箍式快开结构的设计与疲劳分析

文中设计的高压卡箍式快开结构与多层包扎筒体相连接,属于径向自紧式密封结构,具有优良密封效果。在对其进行常规计算并初步确定主体结构尺寸后,运用有限元软件ANSYS建立了相关的静力计算模型,计算了设计工况下卡箍式快开结构各部件的应力。采用线性处理方法,按照JB 4732—1995(2005年确认),对上平盖、卡箍、筒体端部各个危险截面处进行了应力强度评定和疲劳分析。经计算合格后,确定了卡箍式快开结构各部位的结构尺寸,使其同时满足结构静强度和疲劳强度的要求。     

A math-heuristic algorithm for the integrated air service recovery

A sophisticated flight schedule might be easily disrupted due to adverse weather, aircraft mechanical failures, crew absences, etc. Airlines incur huge costs stemming from such flight schedule disruptions in addition to the serious inconveniences experienced by passengers. Therefore, an efficient recovery solution that simultaneously decreases an airline's recovery cost while simultaneously mitigating passenger dissatisfaction is of great importance to the airline industry. In this paper, we study the integrated airline service recovery problem in which the aircraft and passenger schedule recovery problems are simultaneously addressed, with the objective of minimizing aircraft recovery and operating costs, passenger itinerary delay cost, and passenger itinerary cancellation cost.Recognizing the inherent difficulty in modeling the integrated airline service recovery problem within a single formulation (due to its huge solution space and quick response requirement), we propose a three-stage sequential math-heuristic framework to efficiently solve this problem, wherein the flight schedules and aircraft rotations are recovered in the first stage, Then, a flight rescheduling problem and passenger schedule recovery problems are iteratively solved in the next two stages. Time-space network flow representations, along with mixed-integer programming formulations, and algorithms that take advantages of the underlying problem structures, are proposed for each of three stages. This algorithm was tested on realistic data provided by the ROADEF 2009 challenge and the computational results reveal that our algorithm generated the best solution in nearly 72% of the test instances, and a near-optimal solution was achieved in the remaining instances within an acceptable timeframe. Furthermore, we also ran additional computational runs to explore the underlying characteristics of the proposed algorithm, and the recorded insights can serve as a useful guide during practical implementations of this algorithm.     

A mixed methods approach to the social assessment of transport infrastructure projects

Transportation - In this paper, we propose a mixed methods quantitative and qualitative approach to capture fully the measurable and less tangible social impacts of transport projects on local...     

Designing robust rapid transit networks with alternative routes

The aim of this paper is to propose a model for the design of a robust rapid transit network. In this paper, a network is said to be robust when the effect of disruption on total trip coverage is minimized. The proposed model is constrained by three different kinds of flow conditions. These constraints will yield a network that provides several alternative routes for given origin–destination pairs, therefore increasing robustness. The paper includes computational experiments which show how the introduction of robustness influences network design. Copyright © 2010 John Wiley & Sons, Ltd.     

内流式锥阀流场的数值模拟与结构优化

锥阀具有密封性能好、过流能力强、响应快、抗污染能力强等特点,在流体输送中得到了广泛的应用。应用PHOENICS流体计算软件及k-ε湍流计算模型,对内流式锥阀的内部流场进行了模拟仿真,研究了流量变化、开度变化对锥阀流场特性的影响。研究结果对分析锥阀的性能、进行流道的结构优化和实际工程应用都具有一定的指导作用。     

Use of infrared thermography for assessing HMA paving and compaction

The assessment of paving and compaction temperatures effect on Hot Mix Asphalt (HMA) properties has been the subject of various researches. The present study aims to build upon these researches, by investigating the effectiveness and practicality of infrared thermography (IRT) as an emerging technology to assess HMA paving and compaction. For this purpose a field experiment was performed using a thermographic system to investigate the impact of the temperature in a paving project where two different types of HMA were used. The recorded mat surface temperatures are used effectively for the identification of temperature differentials, as well the detection of pavement defects. In addition, density-growth curves are developed for the specific mixtures and compaction pattern being used. IRT data is further analyzed for the development of simple HMA cooling models, providing a quick and efficient means to estimate the compaction time. More details and discussion are outlined in the paper.     

A path-size weibit stochastic user equilibrium model

The aim of this paper is to develop a path-size weibit (PSW) route choice model with an equivalent mathematical programming (MP) formulation under the stochastic user equilibrium (SUE) principle that can account for both route overlapping and route-specific perception variance problems. Specifically, the Weibull distributed random error term handles the identically distributed assumption such that the perception variance with respect to different trip lengths can be distinguished, and a path-size factor term is introduced to resolve the route overlapping issue by adjusting the choice probabilities for routes with strong couplings with other routes. A multiplicative Beckmann’s transformation (MBec) combined with an entropy term are used to develop the MP formulation for the PSW-SUE model. A path-based algorithm based on the partial linearization method is adopted for solving the PSW-SUE model. Numerical examples are also provided to illustrate features of the PSW-SUE model and its differences compared to some existing SUE models as well as its applicability on a real-size network.